The present invention relates to a method for thinning fruit blossoms involving applying an effective amount of a blossom thinning composition to the blossoms and associated living tissue (e.g., nearby buds and leaves) of fruit bearing plants (e.g., fruit tree), the blossom thinning composition comprising eugenol as an active ingredient for the purpose of blossom thinning.
Peach and apple trees produce heavy crop loads that require thinning to ensure that the fruit will achieve marketable size and that flower bloom is not inhibited the following year (Wertheim, S. J., Plant Growth Regulation, 31: 85-100 (2000)). Removing 50% of peach flowers has been shown to increase average size of the remaining fruit and increase overall crop value (Myers, S. C., et al., HortScience, 37: 647-650 (2002)). Growers can spend $1730 per ha to hand-remove excess blossoms and this expense translates to annual costs of over $156,000,000 in the U.S. Chemical thinning of peach flowers reduced the estimated costs of hand thinning up to
310 per ha (Southwick, S. M., et al., J. Amer. Soc. Hort. Sci., 120: 1087-1095 (1995)). Buds, blossoms, and fruit are removed by hand or with chemicals, but few chemical thinners are available and those available are not always effective (Costa, G., et al., Rivista di Furtticoltura e di Ortofloricoltura, 66: 48-54 (2004)). There is a need for new chemical thinners, especially environmentally-friendly thinners, to replace the costly, labor-intensive hand thinning that is currently used by growers (Dennis, F. G., Plant Growth Regulation, 31: 1-16 (2000)).
We have found that eugenol (2-methoxy-4-(2-propenyl)phenol; FIG. 1) acts as a blossom thinner in fruit trees (e.g., peach, apple, pear).